A mobile node (MN for short) is a mobile terminal device such as a mobile phone, a tablet computer, or a portable computer. Because of mobility of the MN, the MN moves among multiple Internet Protocol (IP for short) subnets. To ensure that the MN can still communicate with a correspondent node (CN for short) after the MN moves among the IP subnets, a mobility management solution emerges accordingly.
At present, a distributed mobility management solution is relatively widely applied. A distributed mobility management (DMM for short) network architecture includes multiple IP subnets. An IP address anchor is correspondingly deployed for each IP subnet. On a DMM network, an existing IP address management method is as follows: When an MN moves from a first IP subnet to a second IP subnet, an IP address anchor on the second IP subnet allocates an IP address prefix to the MN. Then, the IP address anchor provides the MN with the IP address prefix allocated by the IP address anchor and a valid IP address prefix being used by the MN, so that by using the IP address prefix, the MN continues with an existing network session or initiates a new network session.
In a process of implementing the present invention, the inventor finds that the prior art has at least the following disadvantage: Because one IP address anchor may allocate different IP address prefixes, an MN cannot accurately determine, according to a change status of a received IP address prefix, whether an IP subnet accessed by the MN has changed.